DIY chimney

bobhangsit

Hi, this is my first post here.

I thought I would wait to see if anyone replies before posting full details including pics, etc.

Anyway, we bought a small wood burning stove last year to heat the basement of our house in Greece. Not knowing anything about them at the time, I thought that a pipe going to the outside would be sufficient for the exhaust. After filling the room with smoke a couple of times I did some more research on the dynamics of air flow in a chimney system.

Lack of money last year prevented us from contracting a professional to properly install this thing and this year the situation is even worse. So any advice in this direction will not be useful at all. Even though I am not qualified, this is a project that I Must do myself as a matter of survival.

Last year I rigged up a temporary solution that worked reasonably well but this year I want to do something more permanent that will work as well as I can make it with my limited resources. I have a design in mind and am looking for opinions from anyone who is knowledgeable about chimneys about whether it will work or not.

Thank, Bob.

Here are a couple of views of what I had last year:

wayoutwest

Welcome to Boards Bob.
I think before anyone can give you advice on whether it will work or not-you'll have to post up de details.
Basic guidelines would be things like:

*keep the flue diameter consistant all the way up.

* " " " " the same as the diameter of stove outlet [Never reduce]

*Don't have any horizontal that are runs longer than 150mm

*keep top of chimney above ridge line of roof [avoids turbulence and therefore preventing downdraughts].

I'm sure that there's a few folk here in DIY that will add to this list.

wayoutwest

I see that you 've now uploaded the pictures.......The first thing that came in to my head was 'O my god'....and the second thing was 'howdya clean it???'.:eek:

bobhangsit

Thanks for the reply, wayoutwest. The contraption in the pics above was never meant to stay after last year so cleaning it wasn't a concern.
What I plan to do this year is replace the flex pipe with a solid galvanized pipe attached close to the wall and going through the roof, wrapped with a layer of rock wool and then wrapped with foil backed glass insulation and all that boxed in with cement board.
Here's a pic of the house from the opposite side:


The circled chimney is for the fireplace on the ground floor and we have no problems with it. Most of the time, the wind blows from left to right in the pic. So I'm figuring that if I put the new chimney at least as high as that, it should be good?

wayoutwest

addition to 'list'

* keep the amount of bends to a minimum


I think your problem may be down to having four bends in your run of flue [+ another, if the flue enters down onto the stove the stove].

wayoutwest

Now I gettit.
What is the vertical measurement between 'facia' and top of existing chimney?

bobhangsit

To follow the offset of the wall from the ground floor to the basement I'm planning on two 45 degree bends. I'm wondering if I should go to the trouble to make the bend where the pipe enters the house a 45 (2) also instead of a 90 (2) as it is now. I'm also not sure if the insulation around the pipe will be enough to prevent damage to the cement board box around it and how far above the box I can extend the pipe with the cowl.

bobhangsit

I measured the existing chimney from its high point on the roof and got just about 2 meters. I had thought about making a hole with a good amount of clearance around the chimney and leaving it open except I think it would allow rain water to run down the wall.

wayoutwest

Are you saying the flue presently enters into the top of the stove and is using two 90's [and a horizontal length] to take it out and up?...if so what is the length of the horizontal ?. What is distance between back of stove and out side face of wall?
45 degree bends are advised,rather than 90 degree ones[less impedence of flow/draw].....And I'm not 100% sure, but I've got a feeling that the regs say that there can't be more than two of them in any given run of flue...better check that.

Once you've decided how the flue breaches the wall, I would try and aim for a completely straight run all the way up using strap fixings to project it enough so it clears the 'stepped out' upper floor.

The flue could pass through the roof by cutting an over sized hole through the soffit boards and pantiles-and using some lead [up under the tiles,and down and around the flue]to span and weatherproof the gap.I'd guess that some sort of insulated, twinwalled section would want to be used at this point to avoid fire hazzard [esp. in extreme heat conditions ie: a chimney fire]

How you are going to clean the flue chimney would be another consideration- through the burner and up? or up from the bottom [outside]? or down from the top?

bobhangsit

All of my problems with this project follow the lack of money. One of the biggest is access. My metal scaffolding is sitting on top of a wooden construction and is still not high enough. More than likely I'll be working on a ladder on top of all this. Last year I did most of the work in the rain. So what I'm trying to do now before the rains come is get the top of this thing built and have the remainder relatively easy to reach. It may be that this will be all that I'll be able to accomplish this year. I understand that protecting the flue pipe from the cold is what prevents condensation of flue gases from forming creosote deposits and increasing the danger of chimney fires. I figure I'll be doing good if I can build the box for the pipe up to 2 meters. After that I need to know if I'll gain anything by extending the pipe up out of the box. Again, thanks for you helpful responses, wayoutwest.

wayoutwest

Cutting through roof and installing lead flashings will involve having SAFE access upto and onto the roof. You really need to put up some proper scaffolding with bracing, from solid ground up and past the facia level,in order to do this job.

I've got a good head for heights [worked on dozens of roofs], but the thought of doing this job from a ladder [that is on lightweight tower that is on wooden thing] makes me feel a touch queezy [understatement].

Al Capwned

wayoutwest wrote: »

Cutting through roof and installing lead flashings will involve having SAFE access upto and onto the roof. You really need to put up some proper scaffolding with bracing, from solid ground up and past the facia level,in order to do this job.

I've got a good head for heights [worked on dozens of roofs], but the thought of doing this job from a ladder [that is on lightweight tower that is on wooden thing] makes me feel a touch queezy [understatement].

This..... Whatever you do, make sure you're safe doing it.

Be an awful shame for this thread to suddenly stop with no word from you, OP. Would leave us all wondering if....... :eek:

bobhangsit

I appreciate all of your concern for my safety. I'm doing everything I can to minimize the risks. Any input on the design I've proposed will help to keep me from doing this again. Thanks again, Bob.

wayoutwest

If Greece is anything like Ireland at the moment, ie:up burst bubble ****creek,is there not a glut of second-hand scaffolding to be got hold of locally? - like there is here.

P.S - How long is a Greek winter and how cold does it get?......I always imagined greece as being warrm + sunny[excuse ignorance].

bobhangsit

I don't know about the southern part of the country, say in Athens, but here in the north (Thessaloniki) from about November to March the temps hover around freezing. I had to look to find out what units of measure Ireland uses to know whether to say 0 or 32 so don't apologize for ignorance. Maybe 2 or 3 times a winter we might get some snow.


We're up on a hill at about 800 meters so we get it more than down in town.

I heard one American politician say that if the economy in the states gets as bad as in Greece...

We have a very nice oil burning furnace that we can't afford to fill which is the reason we've moved to the basement where it's warmer in the winter and cooler in the summer. There may be some scaffolding I could get cheap but any money I spend on this project is going to take away from what we'll have to buy wood, food, electricity etc.

For 20 years in the states and about 5 here, I worked installing drywall in houses and commercial buildings. A lot of the time I was doing things much more dangerous than this thing. So even though this won't be a cake walk, it won't be any worse than what I've dealt with many times before with much less at stake.

wayoutwest

Bob - wos just wondering how much you have to pay for a cubic metre of [loosethrown] logs and what type of timber is available......[sorry to divert thread a bit.]

bobhangsit

Well, I'm not holding out much hope that I'll get the info I'm looking for before I need it now. We pay for wood by weight and I think it's around 125€ per metric ton. I think some of it is oak and one other type that I don't know what kind of tree it is.

wayoutwest

125 euro a tonne, is'nt cheap [about the same as here, for quality,seasomed,hardwood]:)

bobhangsit

The question about wood isn't so far off the topic as I first thought because the wood that we get in Thessaloniki is Not seasoned. In fact far from it. Most of the sellers here store their wood uncovered and I suspect that much of it has been cut the same year they sell it. So when we burn it, water boils out of the ends of the pieces. So that brings back the question of how much of the flue pipe can I leave exposed on top to get the height I need and still be able to reach high enough to construct the surrounding box.

Qualitymark

Does this help?

http://www.youtube.com/watch?v=_AegPjcHS5I

(It's a YouTube instructional video on installing wood stoves.)

If you're using wet wood you'll gunge up the chimney. I got a present of a cube of kiln-dried wood last year and it's seen us through almost 12 months - unbelievable heat and burns wonderfully. Expensive, but I'll buy a new lot for this winter if possible.

If you can, buy a load of wood and put it somewhere that it can dry out, with a bit of a roof over the top so it doesn't get rained on.

A moisture meter like this http://www.ebay.co.uk/itm/Digital-Moisture-Meter-Wood-Timber-Damp-Detector-Tester-with-free-Battery-/110954745407?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item19d56b0e3f will show you when the wood's dry enough to burn. (As far as I remember, around 12% - I don't need to measure it since switching to kiln-dried.)

Greece! You lucky sucker!

wayoutwest

Bob -125 euro/tonne for piss wet logs sounds like a piss take to me. Burning logs that have more than a 15 -20% moisture content,will yield half the heat that you'd get from dry ones + deposits LOTS of sticky, resinus,HIGHLY INFLAMMABLE tar = almiighty rocket of a chimney fire [and/or stove and flue rotting away from the acid]. Burning wet wood is also extremely bad for the environment and ecologically,negates any 'plus points scored by using a 'sustainable'[not fossil] fuel.

.......back to the design....I think you need to know whether you should be using single wall or twin wall in this [external] situation, before thinking about boxing in etc. I hav'nt dealt with external fluwork like this so.......are there any pro solid-fuel fitters out there with this answer??......if not - maybe try asking over in the 'Pumbing and Heating' forum.

All the best, Wayoutwest.

bobhangsit

nice vid, Qualitymark, ty
next time I'm in the states trying to install a $2000 wood stove in a wood frame house I'll try it that way.

Qualitymark

bobhangsit wrote: »

nice vid, Qualitymark, ty
next time I'm in the states trying to install a $2000 wood stove in a wood frame house I'll try it that way.

Glad you liked it; I hope any suggestion I make to help will be met with such courteous kindness.

YouTube is a great source of help for doing all kinds of things - sanded a floor last year with its help.

sooty_soupy

Just been asked to get involved guys, but from what I can gather the original photos have been removed so I am blind apart from creating a picture from reading the posts.

My initial thoughts are that there are bends, potentially horizontal runs and from what I can deduce there is no mention of insulated flue systems apart from what might be used through the sofit.

Clearly if finances are going to be an issue, what I would propose might be out of your budget, but I would always encourage flue gases to rise at all times. As Wayoutwest said, reduce the amount of bends in the flue and keep them as shallow as possible. I would always aim to use 30 degree bends as opposed to 45's for instance.

Is there any chance of taking insulated flue through the ceiling, up through the roof in a flashing system and keeping the flue within the property as long as possible? If you experience extremes of cold, then keeping the flue within the home as long as possible makes much more sense, plus any radiant heat is not wasted to the outside world, but capitalised on. This way a vertical flue would be very easy to achieve, but more importantly the cooling effect on flue gasses is minimised. You will still nee to gain access to the roof to fit the flue and flashing, but as long as you maintain the clearances from combustibles that the manufacturer requires, then this is a perfectly safe installation, and is a win win all round. You just need to be sure that you use the correct support systems through the joists and rafters of the home, and use the correct firestops. It will cost what it costs for the materials, but I'm sure if you are doing the work yourself, it would help reduce the bill. If anything, then you have a safe and functioning heating system.

Hop this helps.

David

bobhangsit

Thanks for the reply, David.

If your initial thoughts are about the bends in the pipes, I guess this is the most important thing?

I'm living in a house in Greece whose construction is fairly typical here. That is, concrete floors and ceilings supported by concrete columns and beams with brick interior walls. The sloped roof is built above the flat ceiling of the uppermost floor with a wood frame supporting terracotta tiles.

To run a flue pipe from the basement to the roof on the inside of the house would mean going through three concrete ceilings/floors of approximately 10 inches thickness each. This is not really viable especially since I could be going through water pipes embedded in the concrete.

So what I've decided to do is run my pipe from the inside of the basement up the wall on the outside of the house. I'm using a single walled stainless pipe that I'm going to wrap with 3cm of rock wool and box that in with cement board.

After the number of bends and the angles of the bends (I think I'll only be able to find 45 degree pieces of pipe angles), I have two big questions. How critical is the total height of the stack and how much of the pipe can extend out of the box unprotected by insulation.

btw I deleted the pics in my original post and was going to replace them with new ones and now I see I can no longer edit that post. I'll put up some new pics later on this morning. Thanks again, Bob.

bobhangsit

Here's where we're at now:



Just waiting on a cap and some more scaffold.